ECC/tests/hooks
Jamkris 4f21ed2acf fix(hooks): use last cumulative row for session cost in metrics bridge
`ecc-metrics-bridge.js#readSessionCost` summed the
`estimated_cost_usd`, `input_tokens`, and `output_tokens` of
every matching row in `~/.claude/metrics/costs.jsonl`. That breaks
the documented contract of `scripts/hooks/cost-tracker.js`, which
explicitly states (in its module docblock):

  Cumulative behavior: Stop fires per assistant response, not
  per session. Each row therefore represents the cumulative
  session total up to that point. To get per-session cost, take
  the last row per session_id.

Summing N cumulative rows over-counts by roughly (N+1)/2 ×. For a
session with 3 rows at 0.01, 0.02, 0.03 USD (true running total
0.03), the bridge today reports 0.06 USD. The over-counted value
feeds `ecc-context-monitor.js`, which then trips its
COST_NOTICE_USD / COST_WARNING_USD / COST_CRITICAL_USD thresholds
on phantom spend AND injects the inflated number as
`additionalContext` into the live model turn — so the agent
itself is told a wrong cost.

Reproduced on `main` before this commit:

  $ cat > /tmp/eccc/.claude/metrics/costs.jsonl <<EOF
  {"session_id":"S1","estimated_cost_usd":0.01,"input_tokens":333,"output_tokens":166}
  {"session_id":"S1","estimated_cost_usd":0.02,"input_tokens":666,"output_tokens":333}
  {"session_id":"S1","estimated_cost_usd":0.03,"input_tokens":1000,"output_tokens":500}
  EOF

  $ HOME=/tmp/eccc node -e 'const m = require("./scripts/hooks/ecc-metrics-bridge.js"); \
      console.log(JSON.stringify(m.readSessionCost("S1")))'
  {"totalCost":0.06,"totalIn":1999,"totalOut":999}

Expected: `{"totalCost":0.03,"totalIn":1000,"totalOut":500}` (the
last cumulative row).
Actual: 2× over-count.

Fix: replace `+=` with `=` in the matching branch so the assigned
values reflect the most recent row encountered. The iteration
order is file order, which is also event time order, so the last
assignment wins — exactly the contract cost-tracker writes
against.

After this commit the reproduction above returns
`{"totalCost":0.03,"totalIn":1000,"totalOut":500}`.

Regression test in `tests/hooks/ecc-metrics-bridge.test.js`:
`readSessionCost returns the LAST cumulative row, not the sum
(cost-tracker contract)`. The existing
`readSessionCost does not include unrelated default-session rows`
test happened to pass even with the bug because it only had one
target-session row — single-row sessions are coincidentally
correct under both formulas. The new test uses three rows so the
two formulas diverge.

A second issue in the same function — the 8 KiB tail-only read
silently drops older rows once a session's recent cumulative
totals scroll past that window — is fixed in the next commit.
2026-05-17 21:41:24 -04:00
..
auto-tmux-dev.test.js feat: add C++ language support and hook tests (#539) 2026-03-16 14:31:49 -07:00
bash-hook-dispatcher.test.js fix: consolidate bash hooks without fork storms 2026-04-14 21:23:57 -07:00
block-no-verify.test.js fix: close block-no-verify bypass holes 2026-05-12 22:28:12 -04:00
check-hook-enabled.test.js feat: add C++ language support and hook tests (#539) 2026-03-16 14:31:49 -07:00
config-protection.test.js fix: integrate recent hook and docs PRs (#1905) 2026-05-14 21:37:28 -04:00
continuous-learning-observe-runner.test.js fix: route continuous learning observe hooks through node 2026-04-29 21:28:59 -04:00
cost-tracker.test.js fix: integrate recent hook and docs PRs (#1905) 2026-05-14 21:37:28 -04:00
design-quality-check.test.js feat: add web frontend rules and design quality hook 2026-04-02 17:33:17 -07:00
detect-project-worktree.test.js fix(tests): resolve Windows CI test failures (#701) 2026-03-20 03:37:21 -07:00
doc-file-warning.test.js refactor: address reviewer feedback 2026-03-29 10:09:02 +08:00
ecc-context-monitor.test.js fix: add context monitor cost warning opt-out 2026-05-17 01:53:57 -04:00
ecc-metrics-bridge.test.js fix(hooks): use last cumulative row for session cost in metrics bridge 2026-05-17 21:41:24 -04:00
ecc-statusline.test.js chore: update statusline ANSI color palette 2026-05-15 23:18:01 -04:00
evaluate-session.test.js fix: remove unused execFileSync import (no-unused-vars ESLint) 2026-02-18 07:15:53 +05:30
gateguard-fact-force.test.js fix(hooks): close grouped command bypasses in gateguard (#1912) 2026-05-15 01:39:15 -04:00
governance-capture.test.js fix: resolve blocker PR validation regressions 2026-03-25 01:34:29 -04:00
hook-flags.test.js feat: add C++ language support and hook tests (#539) 2026-03-16 14:31:49 -07:00
hooks.test.js fix: scope SessionStart context injection 2026-05-11 22:56:29 -04:00
insaits-security-monitor.test.js test: relax InsAIts monitor timeout 2026-05-11 19:38:21 -04:00
insaits-security-wrapper.test.js test: harden InsAIts wrapper fake Python shim 2026-05-12 01:13:01 -04:00
mcp-health-check.test.js test: stabilize MCP stderr probe timeout 2026-05-12 01:13:01 -04:00
observe-subdirectory-detection.test.js fix: salvage remaining stale queue fixes (#1754) 2026-05-11 16:41:08 -04:00
observer-memory.test.js fix: reduce observer hook scanner signatures 2026-05-16 15:26:25 -04:00
plugin-hook-bootstrap.test.js test: cover hook bootstrap and InsAIts monitor 2026-04-29 17:45:22 -04:00
post-bash-hooks.test.js feat: add C++ language support and hook tests (#539) 2026-03-16 14:31:49 -07:00
pre-bash-commit-quality.test.js fix: run pre-bash linters through windows wrappers 2026-04-29 18:59:10 -04:00
pre-bash-dev-server-block.test.js fix: integrate recent hook and docs PRs (#1905) 2026-05-14 21:37:28 -04:00
pre-bash-reminders.test.js feat: add C++ language support and hook tests (#539) 2026-03-16 14:31:49 -07:00
quality-gate.test.js feat: add C++ language support and hook tests (#539) 2026-03-16 14:31:49 -07:00
session-activity-tracker.test.js test: cover session activity tracker edge paths 2026-04-29 18:15:51 -04:00
stop-format-typecheck.test.js perf(hooks): batch format+typecheck at Stop instead of per Edit (#746) 2026-03-31 14:12:12 -07:00
suggest-compact.test.js fix: integrate recent hook and docs PRs (#1905) 2026-05-14 21:37:28 -04:00
test_insaits_security_monitor.py test: cover hook bootstrap and InsAIts monitor 2026-04-29 17:45:22 -04:00